Skirt facility for a ground-effect machine

ABSTRACT

An elementary cell adapted to be assembled together with other similar cells to form a compartmented-skirt facility for a ground-effect machine, the cell being formed by an outer wall element and inner wall element bounding together a substantially crescent-shaped space, such cell being adapted to be mounted and demounted individually on the structure of a ground-effect machine.

United States Patent Marchetti et a].

451 Aug. 1, 1972 [54] SKIRT FACILITY FOR A GROUND- EFFECT MACHINE [72] Inventors: Charles Joseph Marchetti, Neuillysur-Seine; Marc Henri Jean Faure, Saint-Maur-des-Fosses, both of France [73] Assignee: Societe DEtudes et de Development des Aeroglisseurs Marius Terrestres France [22] Filed: Dec. 30, 1969 [21 Appl. No.: 889,166

[30] Foreign Application Priority Data Dec. 30, 1968 France ..68l82226 [52] US. Cl ..180/121, 180/127 [51] Int. Cl ..B60v 1/16 [58] Field of Search ..180/127, 128, 118, 121

[56] References Cited UNITED STATES PATENTS 3,420,330 l/ 1969 Bliss ..180/ 127 X 3,504,755 4/1970 Bliss et al ..180/118 Primary Examiner-A. Harry Levy Att0rney-Brufsky, Staas, Breiner and Halsey [57] ABSTRACT An elementary cell adapted to be assembled together with other similar cellsto form a compartmented-skirt facility for a ground-effect machine, the cell being formed by an outer wall element and inner wall element bounding together a substantially crescentshaped space, such cell being adapted to be mounted and demounted individually on the structure of ground-effect machine.

11 Claims, 9 Drawing Figures mzmsnwc' nan A SHEET 3 OF 5 FIG. :8

SKIRT FACILITY FOR A GROUND-EFFECT MACHINE This invention relates to an improved skirt facility for ground-efiect machines.

One known suggestion for roll and pitch stabilization of a ground-effect machine is to multiply the number of pressure-fluid cushions by subdividing into a plurality of compartments the space where such cushions are formed. It has also been proposed to reduce fluid consumption by recovering fluid leaking from one or more central compartments to at least partly supply one or more peripheral compartments.

Various skirt constructions can be devised along these lines; this invention is for improvements in or relating to a known skirt facility comprising in combination a first endless wall bounding a first cushion compartment which is supplied with pressure fluid, a second endless wall extending around the first wall, means for dividing the space between the two endless walls into at least two other cushion compartments, communications being so devised between the first compartment and the other compartments that the latter are supplied with pressure fluid from the first compartment, to which all the fluid is delivered.

According to this invention, the compartmentedskirt facility is embodied by a large number of individual cells which are adapted to be readily assembled and disassembled individually and which are disposed in consecutive relationship, each cell being formed by an outer wall element and an inner wall element bounding together a substantially crescentshaped space whose convexity faces outwards and whose tips face inwards. The sequence of the outer wall elements of the various cells forms a multilobed peripheral skirt; similarly, the sequence of the inner wall elements of the various cells forms a multilobed inner skirt, the lobes of the peripheral skirt coinciding with the lobes of the inner skirt.

In one form of this invention, each crescent-shaped cell has a U-shaped frame on which the wall elements are hung and via which the cell can be secured to a structure of the machine, e.g., the bottom surface of the machine platform.

In the accompanying drawings:

FIG. I is a perspective view of a cell according to the invention;

FIG. 2 is a development in plan view elements of the cell of FIG. 1;

FIGS. 3 and 4 are partial views in vertical section of a ground-effect platform with a cell of this kind mounted below it;

FIGS. 5-7 are diagrammatic plan views showing sundry overall shapes, and

FIGS. 8-10 are diagrammatic views, in side elevation, front elevation and perspective respectively, of an improvement in or relating to cells disposed at the rear of a platform.

The elementary cell shown in FIGS. 1 and 2 mainly comprises a metal or timber or plastics frame 1 which in shape substantially resembles a U and to which two pieces of hermetic fabric are secured to form, respectively, an outer flexible wall element 2 convex towards outside space 3 and an inner flexible wall element 4 concave towards inside space plenum chamber 5. The inner wall element 4 has an outer portion which faces of the two wall the plenum chamber 5 and a pair of side portions which extend inwardly from said outer portion towards said plenum chamber. The outer wall element 2 has an outer portion which faces the outer portion of the inner wall element 4, and a pair of side portions which embrace the respective side portions of the inner wall element. The two wall elements 2, 4 bound between them a substantially crescent-shaped intermediate space 6.

The cell thus embodied is rigidly mounted, in a manner suitable for rapid assembly and disassembly, under a structure or platform 7 of a ground-effect machine, as can be seen in FIG. 3. It will be seen that the respective upper edges of the inner and outer wall elements are fixed to the machine structure 7 in such relative positions that, in the vicinity of said upper edges, the respective outer portions of said wall elements are positively kept at a distance from one another. The machine has a ducted fan 8 which delivers compressed air, in the direction indicated by arrows F I, to the plenum chamber 5 to form a central cushion therein. Air leaves plenum chamber 5 in one direction, indicated by an arrow F2, through the gap between the free lower edge 40 of inner wall element 4 and the ground or bearing surface 9, and in another direction, indicated by an arrow F3, through the gap left between a portion of the upper edge 4b of element 4 and platform 7, said air supplying the space 6 to form a peripheral cushion therein. The air finally escapes to atmosphere, in the direction indicated by an arrow F4, through the gap between the lower free edge 2a of the outer wall element 2 and the ground 9.

The frame I, being U-shaped, can be adapted not only to a horizontal plane, as shown in FIG. 3, but also to an inclined plane, as shown in FIG. 4.

The skirt facility according to the invention is embodied by a sequence right around the platform f a large number-between 20 and lOO-of elementary cells such as the cell just described. As will be seen, the sequential side-by-side relationship of the elementary cells is such that a side portion of the outer wall element of each cell is substantially contiguous with an adjacent side portion of the outer wall element of a neighboring cell. Clearly, if the frames 1 used have parallel or converging U arms, a machine having in plan any shape can be fitted up, and some non-limitative examples are given in FIGS. 5-7.

Referring to FIG. 5, the machine is in plan circular and its skirt facility is formed by 24 identical elementary cells, the frames of which have converging arms.

The machine of FIG. 6 is in plan oblong and has a skirt facility comprising 24 elementary cells, the frames of which have parallel arms, and 12 cells, the frames of which have converging arms. A feature of said machine is that it can be dismantled in three parts along the line: All!l and CD, each part retaining its own elementary ce s.

The machine shown in FIG. 7 has a shape which tapers towards the front.

Even more complex shapes can be produced by using cells in which the arms of the U are divergent.

In all of FIGS. 5-7, the central compartment or plenum chamber 5 and the peripheral compartment 6 formed by juxtaposition of the elementary cells 'are clearly visible.

As will be apparent:

a. adjacent elementary cells are tangential to one another; I

b. their non-tangentialparts are cylinder or. cone elements whose axes are convergent below the platform.

The support frame 1 is formed by'two straight lines connected to an ellipse arc, and the development of the wall elements 2, 4 (see FIG. 2) corresponds to two straight lines D1, D2 connected by a sinusoidal arc S at the top, whereas the bottom part comprises just a single straight line D3 (cylindrical wall corresponding to a parallel-arm frame '1) ortwo straight lines joined together by asinusoidal arc (conical wall corresponding to a convergent-arm frame 1 g The inner wall element 4 is apertured so that air can flow through at the top in the direction indicated by the arrow F3 (FIGS. 3 and 4) from the plenum chamber 5 to the peripheral compartments 6. This passage corresponds to a cross-section of approximately 1 to, 2 percent of the total bearing surfaceof the vehicle.

Thereis some risk of the rear parts of the skirt facility hereinbefore described becomingentangled with obstacles (stakes, heavy seas etc); To obviate this disadvantage and to lift theskirt when passing over such obstacles, an improvement resembling a ramp is provided.

As canbe seen in FIGS. 8-10, a grating 10 covers the bottom part of the inclined'plane bounded by the two straight lines D3 of the free lower edge of the wall elements 2, 4 of the cells at the rear of the machine (or, if required, of all: the cells if the machine J is a omnidirectional vehicle). The grating 10 is secured not to .the cells-so that the same are completely free to be dismantled-but to the frame 7, the connection being by way of wires or flexible rods 11 disposed in'the plane separating the plane parts of two consecutiv'e cells. The

wires 11, which aremade, e.g., of steel, must be rigid I I enough 'to bend only slightly as a result of thepressure loss which theycarise. s

Weclaim: 4

1. A ground-effect machineadapted to be supported above a bearing surface, said machinehaving, in combination,

a machine structure;

' V a .skirt facility projecting downwardly from said machine structure towards said bearing surface, saidskirt facility comprising a plurality of elementary cells disposed in sequential side-by-side relationship whereby to bound together with said machine structure a plenum chamber; each said elementary cell including an inner flexible wall element and an outer flexiblewall element having each an upper edge" adjacent th'emachine structure and a free lower edge adjacent the bearing surface; said inner wall element having an outer portion which faces the plenum chamber, and a pair of side portions which extend inwardly from said outer portion towards said plenum chamber, whereby said inner wall element has a concavity to the plenum chamber; said outer wall element having an outer portion which faces the outer portion of the inner wall element, and a pair of side portions which embrace the respective side portions of the inner wall element; the sequential side-by- .side relationship of said elementary cells being such that a side portion of the outer wall element of each cell is substantially contiguous with, an adjacent side portion of the outer wall element of a neighboring cell; means for securing each elementary cell to the machine structure, such as to permit individual mounting and 'demounting thereof, said securing means comprising means for fixing the respective upper edges of said inner and said outer flexible wall elements to the machine structure in-such relative positions that, in the vicinity of said upper edges, the respective outer portions of said wall elements are positively kept at a distance from one another, so as to bound together a substantially crescent-shaped space; passage means extending through the outer portion of the inner. wall elementof each elementary cell in the vicinity of the machine structure, whereby to afiord communication between said plenum chamber and each crescent-shaped space; and means for supplying the plenum chamber with pressurized fluid, whereby said crescent-shaped spaces are. permanently supplied through said passage means with pressurizedfluid from said plenum chamber, when said supply means are operative. 2. A ground-effect machine asset forth in claim 1- wherein said securingmeans comprises, for each elementary cell, a U-frame on which the respective upper edges of the inner-wall element and of the outer wall wherein each wall element is embodied by a piece of hermetic fabric which, when developed in a plane, forms a geometrical figure havingan axis of symmetry and bounded'laterally by two inclined straight lines.

.4. A ground-effect machine as set forth in claim 3 wherein the outer wall element has, when developed in a plane, the general shape of an isosceles triangle the apexof'whichis rounded. Y v

5. A ground-efiect machine as set forth in claim 3 wherein the inner wall element has, when developed in a plane, the general shape of an isosceles trapezium.

6. A ground-effect machine as set forth in claim 1 wherein at least those of the elementary cells which are located at the rear of the machine are provided, each, with gratings disposed beneath the lower free edge of the wall elements thereof.

7. A ground-efiect machine as set forth in claim 6 further comprising flexible wires depending from the machine structureand adapted to be attached to said gratings, whereby said gratings are borne by said molcshine structure independently of the elementary ce wherein said wires are disposed in gaps between coning a free bottom edge, said wall elements being joined 7 at their ends and bounding a substantially crescentshaped space, said bottom edges being disposed in planes directed upwardly and inwardly toward said 8. A ground-efiect machine as set forth in claim 7 cushion space, and a grating disposed along said plane wherein said grating is borne directly by said structure, of said elements disposed at said rear end of said through the agency of flexible wires. machine to lift the same when the machine pales over 11 An demenm n a m forth in claim an obstacle, said cell having means for securing said cell to the machine structure, such as to permit ready 5 m m W m a gap between two individual mounting and demounting thereof.

10. An elementary cell as set forth in claim 9, s s s s 

1. A ground-effect machine adapted to be supported above a bearing surface, said machine having, in combination, a machine structure; a skirt facility projecting downwardly from said machine structure towards said bearing surface, said skirt facility comprising a plurality of elementary cells disposed in sequential side-by-side relationship whereby to bound together with said machine structure a plenum chamber; each said elementary cell including an inner flexible wall element and an outer flexible wall element having each an upper edge adjacent the machine structure and a free lower edge adjacent the bearing surface; said inner wall element having an outer portion which faces the plenum chamber, and a pair of side portions which extend inwardly from said outer portion towards said plenum chamber, whereby said inner wall element has a concavity to the plenum chamber; said outer wall element having an outer portion which faces the outer portion of the inner wall element, and a pair of side portions which embrace the respective side portions of the inner wall element; the sequential side-by-side relationship of said elementary cells being such that a side portion of the outer wall element of each cell is substantially contiguous with an adjacent side portion of the outer wall element of a neighboring cell; means for securing each elementary cell to the machine structure, such as to permit individual mounting and demounting thereof, said securing means comprising means for fixing the respective upper edges of said inner and said outer flexible wall elements to the machine structure in such relative positions that, in the vicinity of said upper edges, the respective outer portions of said wall elements are positively kept at a distance from one another, so as to bound together a substantially crescent-shaped space; passage means extending through the outer portion of the inner wall element of each elementary cell in the vicinity of the machine structure, whereby to afford communication between said plenum chamber and each crescent-shaped space; and means for supplying the plenum chamber with pressurized fluid, whereby said crescent-shaped spaces are permanently supplied through said passage means with pressurized fluid from said plenum chamber, when said supply means are operative.
 2. A ground-effect machine as set forth in claim 1 wherein said securing means comprises, for each elementary cell, a U-frame on which the respective upper edges of the inner wall element and of the outer wall element are fixed, and via which the elementaRy cell can be secured to the machine structure.
 3. A ground-effect machine as set forth in claim 1 wherein each wall element is embodied by a piece of hermetic fabric which, when developed in a plane, forms a geometrical figure having an axis of symmetry and bounded laterally by two inclined straight lines.
 4. A ground-effect machine as set forth in claim 3 wherein the outer wall element has, when developed in a plane, the general shape of an isosceles triangle the apex of which is rounded.
 5. A ground-effect machine as set forth in claim 3 wherein the inner wall element has, when developed in a plane, the general shape of an isosceles trapezium.
 6. A ground-effect machine as set forth in claim 1 wherein at least those of the elementary cells which are located at the rear of the machine are provided, each, with gratings disposed beneath the lower free edge of the wall elements thereof.
 7. A ground-effect machine as set forth in claim 6 further comprising flexible wires depending from the machine structure and adapted to be attached to said gratings, whereby said gratings are borne by said machine structure independently of the elementary cells.
 8. A ground-effect machine as set forth in claim 7 wherein said wires are disposed in gaps between consecutive elementary cells.
 9. An elementary cell adapted to be assembled together with other similar cells arranged side-by-side to form a compartmented-skirt facility for bounding the cushion-space of a ground-effect machine having a front end and a rear end, said cell being formed by an outer wall element and an inner wall element each having a free bottom edge, said wall elements being joined at their ends and bounding a substantially crescent-shaped space, said bottom edges being disposed in planes directed upwardly and inwardly toward said cushion space, and a grating disposed along said plane of said elements disposed at said rear end of said machine to lift the same when the machine passes over an obstacle, said cell having means for securing said cell to the machine structure, such as to permit ready individual mounting and demounting thereof.
 10. An elementary cell as set forth in claim 9, wherein said grating is borne directly by said structure, through the agency of flexible wires.
 11. An elementary cell as set forth in claim 10, wherein said wires are disposed in a gap between two consecutive cells. 